The Large Tortoiseshell was once widespread in southern Britain but declined to extinction by the 1980s. It is a woodland butterfly whose larvae feed mainly on Elm (Ulmus) spp. It is still common in some parts of Europe, but declining in others. There continue to be sporadic records in Britain, but these are largely considered to be of specimens released from reared stock rather than immigrants. (For further details on this species see http://www.butterfly-conservation.org/).

Log collated index plot

This chart shows the index of abundance (LCI = Log Collated Index) over time. It shows fluctuations in
populations from year to year, and is scaled so that the average index over the whole series is equal to 2
(horizontal line). For greater detail about how this index is derived, click on the green question mark above.

Trend description :This rare migrant has been recorded on eleven different UKBMS transects since monitoring began. There is insufficient data to calculate accurate trends in abundance but this species does seem to appearing more and more regularly on transects.

Phenology plot

Phenology plot

This chart shows the average number of butterflies seen on transects between Arpil and October across all sites (fitted values from a Generalised Additive Model). The blue line gives average counts over the full BMS series (1976 to date) and the red line gives the average for the last year.

This map shows symbols for the mean abundance at transect sites, with the colour of the symbol reflecting the level of abundance. Means are over all years. Grey background squares are the occupied cells as shown by the Butterflies for the New Millenium over the previous ten year period.

Coverage

In total, Large Tortoiseshell has been recorded from 1 transects in the Butterfly Monitoring Scheme. Of these, annual indices of abundance have been calculated from 5 sites, with an average index of 0 individuals per site.

For 0 of these sites, Large Tortoiseshell has been recorded well enough to calculate annual indices of abundance in more years, allowing trends to be calculated.

In 2017, 0 individuals were recorded from 0 sites, producing annual indices at 0 of these.

This map shows the trend in abundance at particular transect sites for which data has been received within the last five years. Trends (increasing, declining or stable) are assessed at sites where the species has more than five years of annual index data. Use the option boxes below to view plots for individual sites.